const std = @import("std");
const c = @cImport({
    @cInclude("SDL2/SDL.h");
    @cInclude("termios.h");
});

fn init_ttyacm0(port: [:0]const u8) !std.posix.fd_t {
    const fd = try std.posix.open(port, .{ .ACCMODE = .RDWR, .NOCTTY = true, .SYNC = true }, 0);
    var tty: c.termios = .{};
    if (c.tcgetattr(fd, &tty) != 0) {
        std.posix.close(fd);
        return error.TTY_ERROR;
    }
    _ = c.cfsetospeed(&tty, c.B115200);
    _ = c.cfsetispeed(&tty, c.B115200);
    const csize: c_uint = @intCast(c.CSIZE);
    tty.c_cflag = (tty.c_cflag & ~csize) | c.CS8;
    tty.c_cflag |= (c.CLOCAL | c.CREAD);
    const parenb: c_uint = @intCast(c.PARENB);
    const parodd: c_uint = @intCast(c.PARODD);
    tty.c_cflag &= ~(parenb | parodd);
    const cstopb: c_uint = @intCast(c.CSTOPB);
    tty.c_cflag &= ~cstopb;
    const crtscts: c_uint = @intCast(c.CRTSCTS);
    tty.c_cflag &= ~crtscts;
    const ignbrk: c_uint = @intCast(c.IGNBRK);
    tty.c_iflag &= ~ignbrk;
    tty.c_lflag = 0;
    tty.c_oflag = 0;
    tty.c_cc[c.VMIN] = 1;
    tty.c_cc[c.VTIME] = 5;
    if (c.tcsetattr(fd, c.TCSANOW, &tty) != 0) {
        std.posix.close(fd);
        return error.TTY_INIT;
    }
    return fd;
}

pub fn main() !void {
    const fd = try init_ttyacm0("/dev/ttyACM0");
    defer std.posix.close(fd);
    //     _ = try std.posix.write(fd, "ssss");
    //     _ = std.c.fsync(fd);

    _ = c.SDL_Init(c.SDL_INIT_VIDEO);

    const window = c.SDL_CreateWindow("hello", 0, 0, 800, 600, c.SDL_WINDOW_SHOWN) orelse unreachable;
    const renderer = c.SDL_CreateRenderer(window, 0, 0) orelse unreachable;
    var running = true;

    _ = c.SDL_SetRelativeMouseMode(c.SDL_TRUE); // grabs pointer and delivers relative motion
    _ = c.SDL_ShowCursor(c.SDL_DISABLE); // optional: hide cursor

    var dx_acc: i32 = 0;
    var dy_acc: i32 = 0;

    while (running) {
        var e: c.SDL_Event = undefined;
        while (c.SDL_PollEvent(&e) != 0) {
            switch (e.type) {
                c.SDL_QUIT => {
                    running = false;
                },
                c.SDL_MOUSEMOTION => {
                    const dx = e.motion.xrel; // movement since last event on x
                    const dy = e.motion.yrel; // movement since last event on y
                    dx_acc += dx;
                    dy_acc += dy;
                    const speed = 32;
                    if (dx > 0) {
                        const count: usize = @intCast(@divTrunc(dx_acc, speed));
                        dx_acc = @rem(dx_acc, speed);
                        for (0..count) |_| {
                            _ = try std.posix.write(fd, "l");
                        }
                    } else {
                        const count: usize = @intCast(@divTrunc(@abs(dx_acc), speed));
                        dx_acc = @rem(dx_acc, speed);
                        for (0..count) |_| {
                            _ = try std.posix.write(fd, "j");
                        }
                    }
                    if (dy > 0) {
                        const count: usize = @intCast(@divTrunc(dy_acc, speed));
                        dy_acc = @rem(dy_acc, speed);
                        for (0..count) |_| {
                            _ = try std.posix.write(fd, "k");
                        }
                    } else {
                        const count: usize = @intCast(@divTrunc(@abs(dy_acc), speed));
                        dy_acc = @rem(dy_acc, speed);
                        for (0..count) |_| {
                            _ = try std.posix.write(fd, "i");
                        }
                    }
                },
                //                 c.SDL_KEYDOWN => {
                //                     switch (e.key.keysym.scancode) {
                //                         c.SDL_SCANCODE_W => _ = try std.posix.write(fd, "wwww"),
                //                         c.SDL_SCANCODE_S => _ = try std.posix.write(fd, "ssss"),
                //                         c.SDL_SCANCODE_A => _ = try std.posix.write(fd, "aaaa"),
                //                         c.SDL_SCANCODE_D => _ = try std.posix.write(fd, "dddd"),
                //                         else => {},
                //                     }
                //                 },
                else => {},
            }
        }

        const state: [*]const u8 = c.SDL_GetKeyboardState(null);
        if (state[c.SDL_SCANCODE_W] != 0) _ = try std.posix.write(fd, "w");
        if (state[c.SDL_SCANCODE_S] != 0) _ = try std.posix.write(fd, "s");
        if (state[c.SDL_SCANCODE_A] != 0) _ = try std.posix.write(fd, "a");
        if (state[c.SDL_SCANCODE_D] != 0) _ = try std.posix.write(fd, "d");
        if (state[c.SDL_SCANCODE_SPACE] != 0) _ = try std.posix.write(fd, "e");
        if (state[c.SDL_SCANCODE_LSHIFT] != 0) _ = try std.posix.write(fd, "q");

        _ = c.SDL_SetRenderDrawColor(renderer, 0x11, 0x11, 0x11, 0xFF);
        _ = c.SDL_RenderClear(renderer);
        _ = c.SDL_RenderPresent(renderer);
        c.SDL_Delay(10);
    }
}